Rheostat.



PATENTED JUNE 5, 1906.

G. E. STEVENS.

RH'EOSTAT.

APPLICATION FILED 00112, 1904.

eEvISbeVe/ws,

UNITED STATES PATENT OFElCE.

GEORGE E. STEVENS, OF LYNN, MASSACHUSETTS, ASSlGNOR '.lO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEVV'YORK.

RHEOSTAT.

Specicaton of Letters lPatent.

v Patented June 5, 1906.

Application filed October l2, 1904. Serial No. 228,134.

STEVENS,

relative to its bulk, simple and substantial in structure, efficient in operation, and cheap to manufacture; and it c'onssts in a novel organization and arrangement of parts, together with certain structural features, all `of which will be best understood upon reference to the following description, taken in connection with the accompanying drawin s, in whichigure 1 is a perspective view of a rheostat constructed in accordance with my invention.

Fig. '2 is a sideielevation of the movable contact member, showing the parts in contactengaging position. F1g.' 3 is a similar viewI showing parts in non-engaging position. Fig. 4 is a sectional view of the same, taken on ap ane indicated by the line 4 4 of Fig. 2. Figs.

Y 5, 6, and 7 are detail views of the operatinglever and the coperating contact-carrying plates, and Fig. 8 is a diagram of the electrical connections.

In carrying out the present invention, al-

.`though other forms of resistance may be employed, l preferably employ a unit ofthe type diselosed'in my lprior applic/ation, Serial N o. 193,713, filed February 15, 1904. This resistance unit is made up of an edgewisewoundhelical conductor-ribbon whose turnsl are insulated from eachother and forced together to form a rigidx structure. The 'insulation employed may Be of any desired kind but, preferably, I employ an insulating material which is cementitious in character and which, therefore, serves not only to insulate the turns, but to bind them together, and

thereby increase the rigidity of the structure. `In the (present drawings two such resistance units esignated 10) are mounted side by side upon a suitable supportin -base l1, of

Wood or other insulatingm'ateria The helical windings abut at their upper ends against cylindrical contact-pieces 12, composed of 4copper or like conducting material, and at their lower ends against similar" contacts 'ends ofthe bolts 14 serve as terminals for the windings of the resistance units 10, and the nuts 2() serve to bind the connecting-leads in position. Y

'As clearly illustrated in Fig. 8, the bolts 14 are in electrical connectionwith the resistancewindings at their upper ends, but are insulated therefrom at their lower ends. These bolts are insulatedvfrom the contacts 13 by a suitable insulation 21.V The movable element of the rheostat is mounted on a longitudinallyextending guide-rod 22, located between the resistance units 10 and secured to the base at its opposite ends by suitable lugs 23 24. A retaining-magnet 25, having its polar faces 26 extendin slightly above the surface of the base 11, is located adjacent the upper end of the guide-rod.

The movable member comprises a tubular support 27, which rides along the rod 22. The support 27 is channeled at its opposite sides, as clearly illustrated in Fig. 4, and in these channels are located the oppositely-extending and laterally-movable plates 28 and 29. These plates carry at their outer ends the contacts 30 and 31, which are bent at their opposite ends to conform tothe curvature of the exterior surface of the unit 10, with which they 'are adapted to engage. These contacts are composed of a bundle of laminat-lons, of suitable conducting material, and by reason of their location engage the opposte sides of each of the resistance units which are left exposed and may even be cut away so as to insure good electrical contact.

' An operating-lever 32, provided with a handhold 33 and bifureated Z-sliaped arms 34 35, is pivotally secured to the support 27 by the screws 36 37. An armature 38, adapted to engage the polar face 26 of the retaining-magnet 25, connects the inner-ends of the arms 34 35 of the operating-lever. The c'onneetions between the operating-lever and the contact-supporting plates 28 29 are such that roo when the operating-lever is rocked from the position shown in Fig. 3 to that shown in Fig.

the :fi c 3l) and 31 are draf-,rn each other i lrictional engagement with the opposite ot the-resistance units l0. These connections are established by means oi' scri and slots arranged ns lollowst Sc yws 39 extend through thc slots at() in the arms 3st and .35 and through the slots Ill in the arms 2Q into threaded engagement with the innermost plates as clearly illustrated, and screws 42 extend through slots 43 in the arms and 35 into threaded engagement tif'ith the plates rl"he plates 28 and 29 are also provided with longitudinal slots 44 and 45, through which the pivot-screws 35 and 37 extend. With this organization, as previously indicated, the partial rotation of the operating-lever 32 forcibly draws the concts 530 and Sl toward each other into ennient 'with the iixed element ot the rheos have shown the rheos'tat cond up "ith an, electric motori As there tted the motor-armature 46 is connected directly between one oi'I the leads 47 of the supplv-circuit an d one ot theterminals of the i and the other terminal ot the rheostct is directly connected to the other lead 4S of the supply-circuit. The coil of the retaining-magnet and .the motor held-Winding is connected in series in a branch between the latter terminal and thc line side of the armature. ln the operation of' the device the mo v able m einher normally occupies a position at the lower end ol the re `ts-.nce units 10, and the position ot its parts is that illustrated in Fig. 3. ln this position the contacts 3() and 31 are not in engagement with theresistance units, but rest upon the insulation 2l, which separates the units from their supporting-lugs. rr'hen it is desired to start the motor i 'id'cut out the resistance ot the rhetostat, the operating-lever 32 is drawn upward into the position illustrated in Fig contacts Si) and i3] are therej, Lorceil into iirm engagement with thc tf.l niincl contact members The circuit is then completed between the tern'iinals ot the rheostat through both resisten:.,e-wiiidings and the contsctstl and 3], which bridge the space between the Contact members 13. By drawing upward upon the lever 32 the contacts $3() and 31 slide over the surface ot the resistance units and successively cut out the turns or' the winding, and thereby reduce the amount of resistance in circuiti Finally, when the uppermost position is reached the space between the contact members l2 will be bridged by the movable contacts and all the resistance will be cut out of circuit. ln this position the armature 't8 engages the polar faces 26 of the retaining-magnet, and the magnet being energized holds the parts in this position, even though operator remove his hand toward i energize the retaining-magnet the weight-ed ortion 19 of the lever 32 will be sul'licient to and the ure ot' current in the line or the occurrence of other conditions which will sutliciently derock the parts int'o the posit-ion shown in Fig. '3, thus withdrawing the contacts 3G and 341 from their frictional engagement and allowing the movable contact tc fall under the action of gravity to its normal position.

It will be obvious to those skilled in the art that many alterations and modiiications may be made in the structure which l have herein disclosed without departing from the spiritand scope of my invention. l therefore do not wish to be limited to the speciiic matter disclosed, but aim to cover by the' terms of the appended claims all such alterations and modifications.

What l cla-im as new, and desire to secure by Letters Patent'ot thc United States, is

l. A rheostat comprising two oppositelydisposed resistance units each consisting of a helical insulated conductor having its turns continuously forced together to form a rigid structure, an intermediate guide-rod7 a cooperating sliding contact carried thereby, and electrically-controlled means for maintaining said contact in a predetermined position.

2. A rheostat comprising two oppositelydisposed resistance units eac-h consisting of a helical insulated conductor having its turns continuously forced together to form a rigid structure., an intermediate guide-rod, an a cooperating sliding contactcarried thereby.

3. A rheostat comprising two verticallydisposed elongated resistance units each having an exposed contact-surface extending throughoutits length, an intermediate guiderod, a cooperating sliding contact carried thereby, a retaining-magnet located at the upper end of said rod, and a cooperating armature carried by said contact.

et. A rheostat comprising two verticallydisposed resistance units each consisting of a helical insulated conductor having its turns continuously forced together to form a rigid structure, an intermediate guide-rod, a cooperating sliding contact carried there y, a retaining-magnet located at the upper end of said rod, and a cooperating armature carried by said Contact.

5. A rheostat comprising an elongated resistance unit having an exposed contact-surface extending throughout its length, a cooperating contact movable lengthwise of said unit and laterally into engagement with said surface, and means for giving said contact a lateral movement and then a longitudinal movement in response to a pullin one direction. c 6.. A rheostat comprising a resistance unit consisting of a helical resistance-conductor having its turns continuously forced together I to form a rigid strcture, a coperating contact movable laterall toward and from said unit and longitudinally over its surface, and means for giving said contact a lateral movement and than a longitudinal movement in response to a pull in one direction.

7. In a rheostat, a movable contact member comprising a llongitudinally-movable support, a contact mounted to slide laterally on said support, and means for giving said contact a lateral movement in response to a pull in a longitudinal direction. y

8. In a rheostat, a movable contact member comprisinga longitudinally-movable support, acontact mounted to slide laterally on said support, and a lever pivoted to said support and connected to said contact so as to give it a lat-eral movement in response to a longitudinal pull.

9. In a rheostat, a movable contact mem- Aher comprising a longitudinally-movable support, oppositelv-extending plates mounted to laterally on said sup ort, contacts carried at the outer ends of sai plates, an operating-lever pivoted to said support, and

pin-and-slot connectionsbetween said lever and said plates whereby the movement ofv said lever will )roduce a lateral movement of said plates and contacts. i

10. A rheostat comprising two verticallydisposed resistance units each having exposed contact-surfaces extending throughout its length, an intermediate guide-rod, a contact-support movable thereon, contacts mounted to slide laterally on said slipport into engagement with said contact-su aces, and a weighted lever pivoted to said support and connected to said contacts so as to move them laterally when-rocked and normally holding said contacts in non-engaging position.

l1. A rheostat comprising two verticallydisposed resista-nce units each having exposed contact-slut'zmes extending throughout its length, an intermediate guide-rod, a

contact-support movable thereoncontacts i mounted to slide laterally on said support into engagement with said contact-sur aces7 a weighted lever pivoted to said support and connected to said contacts so as to move them laterally when rocked and normally 'the` end-of t eir movement so as to lock them against return.

13. In arheostat,`a movable contact-carrying member com rising a member movable into and out of frictional engagement with a fixed surface, means for throwing said member into engagement with said surface and moving it over the same, and electromagnetic means for retaining the arts in frictional engagement at the end o their movement so as to lock them against return.

l 14. A rheostat comprising an elongatedl resistance unit having an exposed contactsurface extending throughout its length, a movable contact-carrying member, a contact thereon movable into and out of frictional engagement with said surface', means for throwing said contact into engagement -1 with said surface and moving it over -the same, and means for retaining the arts in frictional engagement so as ,to loc against return.

15. A rheostat comprising an elongated resistance unit having anexposed contactthem surface extending throughout 4its length, a

movable contact-carrying member, a contact thereon movable into and out of frictional engagement with said surface, means for throwing said contact into engagement with said surface and moving 1t over the same, and

electromagnetic means for retainin the parts in frictional engagement so as to ock them against return. In Witness whereof I have hereunto hand this 10th day of October, 1904.

GEORGE E. Y STEVENS.

set my Witnesses:

JOHN A. McMANUs, Jr.,

DUGALD MeK. McKILLoP. 

